It is interesting to see the Bletchley Park discussions about the codebreaking impact being 'overrated'. I think the confusion is that the public forgets that reading the message is just the first step. My own, and possibly incorrect, opinions follow. #thread

1/

Once read, the message needs to be understood to the best of the current capacity within the various level of command. Then a decision as to what to do with it made. This was not done by the code breakers themselves (I'm looking at you @ImitationGame).

2/

Using the North Atlantic as an example, if the SIGINT is actionable then it needs to be filtered by the good people at @WestApproaches and the information issued to convoy and escort commanders.

3/

Then comes the tricky bit, the young men in the Destroyers, Corvettes etc have to search hundreds of miles of open, cold seas to find the young men in the steel tubes and try to kill them before they try to do the same. Note: gif is of an old man.

4/

The hunting, guided by the signals intelligence, turned search areas of thousands of square miles to hundreds and, on rare occasions, tens of miles. Even then, that is still a big area being tossed about in rough seas looking for a small target.

5/

Tools and tactics of the hunt evolved but it still came down to young men hunting other young men using every trick they had learned to grab the momentary advantage to kill, be kill or escape to do it all again later.

6/

I know context is not terribly fashionable in the world today, but it is rather important. Rarely, if ever, do things happen in isolation. A signal is sent, it is read and decisions are taken bu one side or the other. But it is a chain of events that leads to an outcome.

/end